This invention generally relates to the control of temperature and flow distribution of gas streams. More particularly, this invention relates to an apparatus for selectively heating and cooling portions of pre-plated meals carried in dual compartment trays. Specifically, this invention relates to an apparatus for supplying an air flow which will permit selective re-thermalization of certain meal components carried by the tray while other meal components are kept chilled.
The need for a food service system which will allow preparation of meals long before they are needed, hold the meals at a safe temperature, and then reheat portions of the meal for serving has been well recognized. The prior art shows many attempts to develop such systems. Most of these systems presented flaws in either feasibility or expense. For example, both micro-waves and infra-red lamps have been used to re-heat meal portions. These systems were unable to maintain cold meal components on the same tray at the desired cooler serving temperature. This usually required assembly of the meal by adding cold components from a separate refrigerated holding unit.
In my co-pending application, U.S. Ser. No. 480,946 filed June 19, 1974, I disclosed a two-compartment tray for holding cold meal components in one compartment and hot meal components in a second compartment. Prior to serving, both compartments were furnished with cold air to keep the meal portions at a safe temperature. Then, prior to serving, the meal portions to be served hot were re-thermalized by blowing hot air into the compartment carrying these components. The flow of cold air to the other compartment was maintained so that these meal components could be served chilled as required. The present invention is concerned with a specific apparatus for furnishing the desired air flow to the appropriate tray compartment. A refrigeration unit and heating unit may be used to feed two pairs of inlet and outlet manifolds. Nozzles connect the trays to the manifolds. A suitable control means then directs the hot or cold air to the compartment of the tray which carries the metal portions which are to be served hot. Examples of the prior art may be seen in U.S. Pat. Nos. 3,608,770 and 3,784,787.